Abstract:This paper takes the concentration of stress in a locked fault as the model of earthquake source and deals with the changes in the stress field in a three layered media under the lateral boundary condition of a constant rate of displacement loading. The "precursory" changes in apparent resistvity at the surface of the media associated with the changes in stress-strain field is also discussed in this paper in order to reveal the possibil way of connecting the spatial-temporal changes in apparent, resistivity to the source process.
The results show that, the existance of viscous material in the media would play a very importont role in the preparatory process:besides of the influence of structure of the media the extent of stress concentration is closely relative to the viscous property of the media also, And the spatial-temporal distribution of apparent resistivity precursor is not only concerned with the stress-strain field but also with the mechanical and electrical structure condition of media within the detective scalein observational stations.

Abstract:In this paper, the near-field synthetic seismogram for vertical strike slip fault and dip slip fault is discussed with finite difference method in the case of different source depth and fault rupture size (refer to fault rupture size perpendicular to the ground). The acceleration fourier spectrum of different epicentral distance is discussed too.
The following inital results have been obtained through analysing near-field effect of two kinds of sources:
(1) If the source depth and the fault rupture size, are the same, the effect of vertical strike slip fault on near-field surface is larger than the effect of vertical dip slip fault.
(2) For vertical dip slip fault, if the source depth and the fault rupture size are the same, the largest amplitude of the horizontal displacement is larger than one of the vertical displacement in the same epicentral distance.
(3) The largest displacement amplitude produced by anyone of two kinds of sources in the same epicentral distance increases along with the enlargement of rupture size.
(4) The largest displacement amplitude produced by anyone of two kinds of sources in different epicentral distance decreases along with the increasing of epicentral distance, the rate of change along with the increasing of epicentral distance decreases too.
(5) The dominant period of acceleration fourie rspectrum produced by anyone of two kinds of sources in different epicentral distance changes longer along with the increasing of epicentral distance, the dominant period changes longer too along with the increasing of fault rupture size, and long period composition is much too along with the increasing of rupture size.
(6) For anyone of two kinds of sources, owing to the different source depth, the effect on near-field surface is different too. The largest displacement amplitude along with the rate of change of epicentral distance decreases, namely, isoseisms is getting thin. This relation is very useful in determing source depth by isoseisms density.
(7) The dominant period of acceleration fourier spectrum produced by vertical strike slip fault is longer than dip slip fault.

Abstract:The finite element computation for the plant model of containing a group of cracks shows that stress field is homgeneous before the fault slip, but the stress field near the fault changes much large after the fault slip. The direction of the stress field in local area has rotated nearly 90°. It is a possible mechanical mechanism of rotation of P axis in the preearthquake. When the relation of a group of faults in the geology is simulated by the relation of the cracks, the calculation results show that the possibility of slip of some faults is increased, and the possibility of slip of other faults is decreased, because the slip from one of the group of faults. It means that the possibility to occur earthquake is increased for some faults and the one is decreased for other. So, the earthquakes in groups exist the relation under control of the dynamics called the "self-control". Using this result we have divided the "Seismic Curtain" in north China from 1484 to now.

Abstract:In this paper, seismicity indexes A_N-W(b)of Shaanxi, Gansu, Ningxia and Qinghai areas, magnetic storm activity indexes K(b) recorded at Lanzhou Geomagnetic Observatory and sun-sports relative numbers year-average-values R(N) are statisticaly analyzed. We do power spectral analysis and digital filtering. The power spectrum and maximum entropy spectral (MES) analysis of R(N), A_N-W(b) and KSC (b) indicates five main peaks:21, 11, 5, 3and 2 years. Their mutual correlation amplitude and the cross-spectral amplitude represent distinctly that there are above mentioned periods in R (N), A_N-W (b) and KSC (b), too. The correlation analysis showed that correlation coefficient is 0.886 between KSC (b) and A_N-W (b) after perfect low-pass filtering. According to this analysis, that seismicity of Shaanxi, Gansu, Ningxia and Qinghai areas can continue to change stronger in five years is represented. Finally, the mechanism of the seismogenic and triggering process related to the solar activity and magnetic storms is discussed.

Abstract:This paper analyses the relationship between the original times of the historical, recent moderate strong earthquakes and the tilt earth tide. The results show that the original times of earthquakes are located on the peak values of time series of tilt earth tide in the epicentral region; Generally, the original times of isolated events correspond with the maximum values of tilt earth tide in the epicentral region; To the recurrence events in original place, the background of tilt earth tide is similar to that of the original times; The background of tilt earth tide of 70% close events is similar to that of main shocks at the original times; The background of tilt earth tide of 60% strong aftershocks after large earthquakes is similar to that of main shocks at the original times. On the basis of this, we have tried to predict larger aftershocks after the Menyuan earthquake (M=6.4).

Abstract:In this paper, the fault geometric characteristics on various scales are preliminarily studied for the segments of Aerjin south and north fringe fault zones, and the relationship between the geometric characteristics and the seismic activity of the fault zones is quatitatively discussed. Moreover, using the SEM research method for quartz grains from fault gouges, the Holocene activity of some segments of the fault zones is discussed in combination with the macroscopic investigation data, and several microscopic dynamic structures that presumably represent the existence of paleoearthquake events are identified.

Abstract:After almost twenty years of the Xingtai earthquake, more than thirty earthquake swarms and earthquake sequences (M≥4.0) are recorded in Shanxi seismic zone. It is suggested that in earthquake swarm activities of Shanxi, if earthquake swarms with U>0.6, K>0.89, h<1 appear, the mid-strong earthquake will occur in the eastern part of North China. Finally, it is discussed that the relationship between the activities of earthquake swarms and earthquake sequences occurred in Shanxi and the mid-strong earthquakes occurred in North China.

Abstract:混沌理论的提出是自然科学的重大进展,它与自然灾害的预报密切相关。在气象学方面,人们已初步对混沌影响预报的问题作了讨论,其结论是:
(1)影响是有时间期限的,超过这个期限影响才重要,不超过则不重要,这个期限称为预报期限 。

Abstract:兰州台是甘肃省唯一的(Ⅰ类)形变综合观测台,架设有国家地震局地震研究所研制的目前国内最先进的FSQ型自记水管倾斜仪。该台位于(L=103°.7520,λ=36°.0980,H=1550米)兰州市安宁区人防山洞内,洞体进深145米,岩层直立,覆盖层厚29-88米。

Abstract:我们在福建南靖县汤坑进行了水压致裂实验的Eh效应观测。在我国,水压致裂实验已用于石油地质勘探,但用于地震水化效应Eh的观测研究还是首次。本文介绍了观测结果。

Abstract:在1986年8月26日门源6.4级地震前和1984年元月6日武威5.3级地震前,刘家峡地应力站记录到了较明显的前兆异常。但是两次地震前的地应力前兆特征有很大差异。本文介绍了门源地震前的地应力前兆特征,并对产生地应力前兆差异的原因作了初步探讨。

Abstract:传输地震台网是一个包括地震观测和通讯两大技术的综合系统。这一台网正在逐渐取代传统的有人职守地震台站,在地震观测中日益发挥着重要的作用。本文根据传输地震台网的工作特点,对传输地震台的选建和传输通道中涉及到的主要问题进行初步探讨,以期能作为今后开展地震传输工作的参考。

Abstract:中国地震记载虽有数千年的历史,但无烈度和震级量度,仅有文字的直观叙述,如何根据历史记录资料来确定震级,以便进而研究地震分布及其活动规律,这是十分必要的基础工作。

Abstract:在现代地球化学领域里,稳定同位素地球化学是其两大发展方向之一^[1]。不论是在地球的化学组成,还是在地球内部的化学作用及演化方面,稳定同位素都起着"指示"或"示踪"作用。这门学科已逐渐向地震地球化学领域渗透,并且将推动地震地球化学研究的深入发展。

Abstract:在地震预报研究中,关于地球电阻率(地电阻率ρs)与地震关系的研究取得了较大进展。但是,作为一种预报地震的手段,如能得到反映同一本质的其他电性参数的支持,可以增强其预报地震的可靠性。作者认为,岩石的介电常数ε_r,可以用来预报地震,可以与ρs法相配合,互相佐证。

Abstract:This paper collected the data of gravity changes of high precision gravity resurveys networks and earth tide stations during 1970-1985 in China. The relationship between the gravity changes and 11 earthquakes M≥5.0 around the 6 routes and 5 stations has been analyzed. And then the possible mechanisms and characteristics of gravity changes with time have discussed. It is believed that if the moderate strong earthquakes will occur within certain distance from the station, then gravity changes of proper measure would appear before and after earthquakes. The duration T or Tc of gravity change is dependent on the magnitude M, the epicentral distance L and the area of aftershocks S or volume of source V. The gravity changes accompanying an earthquake are mainly caused by underground mass density change apart from crustal deformation. Different features of earthquakes may be verified by the data of gravity and deformation.

Abstract:中国地球物理学会于1988年11月20日-24日在湖南召开了"地球物理灾害学术讨论会"。会议由兰州地震研究所所长郭增建研究员主持,参加会议的有地震、水利、大专院校及科学院等部门的有关专家、学者。会上共交流论文20余篇。著名地球物理学家翁文波、河南省水利科学院王涌泉和赵得秀教授也向大会提交了研究论文及灾害预测意见。